Automatic restart circuit for knitting machines and the like

ABSTRACT

A control circuit for a knitting machine interrupts machine operation in the event that yarn tension is improper as detected by plural stop-motion devices. After a predetermined time period, the machine is automatically restarted if proper tension conditions are restored, but if improper tension remains, the machine is semi-permanently disabled until service personnel can correct the improper conditions and restart the machine manually. A main control relay remains operative for a predetermined delay period after a &#39;&#39;&#39;&#39;tentative stop&#39;&#39;&#39;&#39; for reinitiating machine operation at the end of such time under proper conditions.

KNITTING MACHINES AND THE LIKE Albert A. Kryszek, 5716 S. W. Brugger, Portland, Oreg. 97219 Filed: June 8, 1972 Appl. No.: 260,768

[76] Inventor:

[ 5 6] References Cited UNITED STATES PATENTS 8/1890 Haslam ..340/259 5/1927 Matthews et a1. ..340/259 United States Patent 1 [111 3,735,147 Kryszek 1 May 22, 1973 AUTOMATIC RESTART CIRCUIT FOR Primary Examiner-Robert K. Schaefer Assistant Examiner-M. Ginsburg Attorney-Stephen W. Blore et al..

[5 7] ABSTRACT A control circuit for a knitting machine interrupts machine operation in the event that yarn tension is improper as detected by plural stop-motion devices. After a predetermined time period, the machine is automatically restarted if proper tension conditions are restored, but if improper tension remains, the machine is semi-permanently disabled until service personnel can correct the improper conditions and restart the machine manually. A main control relay remains operative for a predetermined delay period after a tentative stop" for reinitiating machine operation at the end of such time under proper conditions.

13 Claims, 2 Drawing Figures LINE! LINK-12 LINE 3.,

MOTOR Patented May 22, 1973 FIG.

MOTOR FIG. 2

C2 }rl AUTOMATIC RESTART CIRCUIT FOR KNITTING MACHINES AND THE LIKE BACKGROUND OF THE INVENTION Apparatus employing thread or yarn for the manufacture of knitted or woven articles may employ stopmotion devices for interrupting machine operation in the event improper thread or yarn tension is detected. Thus, undesired breaking of threads can be avoided be fore manufacture of an incomplete fabric is caused to occur. Similarly, the end of a roll or spool of thread or yarn is detected by the absence of proper tension. Improper tension for whatever cause generally brings about a semi-permanent interruption in machine operation so appropriate corrective action can be taken by service personnel, after which the machine is manually restarted.

However, in many instances a stop-motion device will make contact momentarily and totally stop the machine when such action may actually be undesired, for example, when an occasional irregularity in yarn trips the stop-motion device. This false stopping causes unnecessary down time for machines and requires unnecessary attention of personnel to restart machines after false stops. It is, however, desirable that themachine be brought to a halt when the stop-motion device is tripped, just in case the tentative stop actually indicates improper tension, so that a faulty fabric will not be manufactured. Also the apparatus is given time to regain the proper tension condition. However,'a multiplicity of quick repetitive starts and stops, merely brought about in direct response to thread or yarn tension, are to be avoided from the standpoint of accurate manufacture of the end product and appropriate care of the machinery.

While restart circuits for machines of this type have been heretofore known, they have generally required a plurality of timing devices and are quite complex and expensive in construction. The cost and reliability of complex devices must be weighed against the time and expense involved in manually restarting machines.

SUMMARY OF THE INVENTION In accordance with the present invention, apparatus is interrupted in operation when incorrect tension is detected by a stop-motion device, and a timing cycle is initiated. If at the end of that timing cycle the correct tension has been restored, the machine is restarted for normal operation. However, if at the end of said period improper tension is still detected, the machine is semipermanently disabled, requiring a manual operation for restart, thus giving service personnel an opportunity to correct the undesired condition. In accordance with an embodiment of the present invention, a control means remains energized after the apparatus is deenergized, indicating the machine has just been on, and a timing cycle is initiated. If at the end of such timing cycle the proper-tension condition has been restored, an automatic restart is initiated via said control means. If at the end of such timing cycle the improper tension remains, the aforesaid control means is disabled, whereby a manual restart will be required for reinitiating machine operation.

It is accordingly an object of the present invention to provide improved restart circuitry for mech-anical apparatus, such mechanical apparatus including a startstop system, and a stop-motion device which indicates incorrect conditions for which shutdown is normally desired.

It is a further object of the present invention to provide an improved automatic restart circuit for knitting machines and other apparatus employing thread or yarn tension means, and to provide an improved restart method.

It is an additional object of the present invention to provide an improved restart circuit for knitting machines and the like which is simple and economical in construction while being reliable in operation.

The subject matter which I regard as my invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. The invention, however, both as to organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings wherein like reference characters refer to like elements.

DRAWINGS FIG. 1 is a partially broken away view of a knitting machine employing apparatus according to the present invention; and

FIG. 2 is a schematic diagram of automatic restart circuitry according to the present invention.

DETAILED DESCRIPTION Referring to the drawings and particularly to FIG. 1, a circular knitting machine is schematically illustrated. Yarn 10 from bobbin 12 passes over arms 14 of a first stop-motion device generally indicated at 16. From there, the yarn extends to a second stop-motion device 18 through which the yarn passes before reaching latch needle 20. Latch needle 20 is supported from a rotating assembly 22 driven by gear motor 24, and, as is well understood by those skilled in the art, the yarn 10 will be engaged by a multiplicity of latch needles during machine operation, only one being shown for simplicity of explanation. Furthermore, a further multiplicity of yarns 10 each withdrawn from its own bobbin and passing through separate stop-motion devices, will be disposed in circular fashion around the knitting machine.

Arms 14 of stop-motion device 16 are adapted to be drawn downwardly in response to yarn tension against a spring tension established in the stop-motion device, excessive yarn tension causing a connection to be made between upper rotating contact 26 and lower flat contact 28 as arms 14 rotate downwardly. Furthermore, slackness or a break in the yarn will be detected by upward movement of member 30, under the influence of counterweight 32, for alternatively causing connection between contacts 26 and 28 as contact 26 rotates in the opposite direction. Contact 26 is cam-shaped, having a substantially flat lower face disposed in nonengagement with contact 28 when normal yarn tension occurs.

In second stop-motion device 18, the yarn passes over weighted tension means 34 wherein weights may be disposed against the yarn over spindle 36, the yarn further passing through eyelets 38, 40 and 42. Eyelet 40 is located at the end of pivotal member 44 springbiased to bring about connection of contacts 46 in the event of slackness in the yarn.

The purpose of the stop-motion devices 16 and 18 is the complete arrest of the knitting machine operation should the yarn become too tight, or break, or otherwise fail to be under the proper tension. It will be appreciated that a correction must be made before resuming knitting operation, in order to prevent the production of a faulty end product. A common example of the detection of improper tension takes place when a particular bobbin runs out of yarn.

However, in many instances a stop-motion device will make contact or trip momentarily and totally stop the knitting machine when such action may be undesired, for example when an occasional irregularity in the yarn passes through the stop-motion device. This false stopping causes unnecessary down time for the knitting machines in a large plate and requires the services of someone to restart knitting machines manually after false stops. It is, however, desired that the machine be brought to a halt in the case of a tentative stop," giving the apparatus time to regain the proper tension condition, avoiding the breaking of yarn, and the like.

Further referring to the automatic restart circuit according to the present invention, reference is made to FIG. 2. Three-phase motor 24 is connected to lines one, two and three via contacts A1, A2 and A3 of a conventional magnetic starter having an operating coil A. For purposes of this application, the magnetic starter, which may be of a conventional type, is referred to as a motor-energizing relay or merely a motor relay.

A control circuit is connected at terminals 1 and 2 to a source of control voltage and includes the operating coil A for the motor relay. The control circuit further includes a start relay coil B having one terminal thereof coupled to terminal 1 through start pushbutton contacts 48 and stop pushbutton contacts 49 disposed serially in that order. The remaining terminal of start relay coil B is coupled, via normally closed contacts D1 and E1, disposed serially in that order, to terminal 2. Normally closed contacts E1 are operated by coil E connected across a pair of motor leads on the load side of a pair of motor relay contacts. Normally closed contacts D1 are operated by the stop-motion devices as hereinafter described.

Start relay coil B is provided with contacts B1 connecting the terminal of the start relay coil on the start pushbutton side thereof to one terminal of a main control relay coil C, said terminal also being coupled to the junction between the start and stop pushbutton via holding contacts Cl associated with main control relay coil C. The remaining terminal of the coil of main control relay C is returned to terminal 2 via the parallel combination of normally closed contacts D2, and normally closed contacts T2, the latter being in series with switch S1. Contacts T2 are associated with a timer as hereinafter described.

Motor relay coil A has a first lead connected to the junction of the start and stop pushbuttons by way of main control relay contacts C2 and start relay contacts B2 disposed in series. Contacts B2 are shunted by holding contacts A4 associated with coil A, as well as by timer contacts T1. The remaining terminal of coil A is returned to terminal 2 via normally closed contacts F1 associated with the stop-motion devices as hereinafter indicated.

A timer operating coil T has one lead connected to the junction between contacts D1 and E1, and the other lead connected to the junction between contacts B1 and main control relay operating coil C. This timer or timing relay is designed to operate its contacts, i.e., the closing of contacts T1 and the opening of contacts T2, after a predetermined time, e.g., after about two to four seconds.

First and second stop-motion relay coils, F and D, are connected to a source of control voltage via the parallel combination of stop-motion device contacts 27 and 47. These correspond, in general, to the contacts of the stop-motion devices 16 and 18 illustrated in FIG. 1, but it will be understood that in a given apparatus, a large number of further stop-motion device contacts will be connected in parallel and are here exemplified by contacts 27 and 47. If any one of these stop-motion contacts close, operating coils D and F will be energized from a control voltage source.

Now considering operation of the FIG. 2 circuit, depression of the start pushbutton closing contacts 48 will energize coil B through normally closed contacts D1 and El, resulting in closure of contacts Bl. Closure of contacts B1 will actuate main control relay operating coil C by way of the start pushbutton contacts 48, contacts B1, and contacts D2, assuming that no stopmotion device is actuated. The main control relay operating coil C closes a circuit through holding contacts CI for maintaining itself in actuated condition although the start pushbutton 48 is depressed for only a short time. Moreover, contacts C2 of the main control relay close, and motor operating coil A is energized by way of contacts C2, start contacts B2, and normally closed contacts F. Althougl'i contacts B2 are only closed as long as the start pushbotton is depressed, as soon as operating coil A is actuated, holding contacts A4 close in parallel with contacts B2 for maintaining operating coil A in actuated condition. The apparatus may be manually stopped at any time by depressing the stop pushbutton for opening contacts 49.

For automatic restart operation, switch S1 will be closed, placing contacts T2 in parallel with contacts D2. Let us assume the motor is operating in normal fashion in response to the starting sequence hereinbefore described. Operating coil E is energized when the motor is energized, whereby normally closed contacts E1 have been opened. Now should improper tension occur, closing contacts of one of the stop-motion devices, relay operating coils F and D will be actuated, relay F opening normally closed contacts Fl. Motor relay coil A is denergized resulting in stopping motor 24 when contacts A1, A2 and A3 open. Consequently, the apparatus will be stopped and knitting operations will cease. Likewise, operating coil B will be deenergized, and normally closed contacts El will return to their normally closed state. Main relay operating coil C is still energized at this time, and timer operating coil T will receive current through contacts Cl and E1, starting a predetermined timing cycle. Let us first assume that a tentative stop has been correctly initiated because of actual improper tension on one of the yarns. At the end of the timing cycle, contacts Tl will close and T2 will open. Contacts T1 could restore the operating circuit for motor relay operating coil A but for the still opened stop-motion relay contacts F1 because the stop-motion device contacts retain the energized condition of coils F and D. Also contacts C2 are open since operating coil C is deenergized through opening of contacts T2, while contacts D2 are open. Consequently, the machine will be permanently shut down until restarted manually as in the case of the usual manual starting circuit. That is, after operating coil C is deenergized at the end of the timing cycle, subsequent opening of the stop-motion device contacts will not restart the machine.

However, if the tentative stop was indicative of a momentarily improper tension, the stop-motion device contacts will open and contacts D2 and F1 will return to their normally closed state before the end of the timing cycle. Then, when timer contacts T2 open, contacts D2 will'have closed and main control relay coil will remain energized. Consequently, timer contacts T1 can recomplete the circuit for motor operating coil A through main control relay contacts C2, which have remained closed, and contacts Fl which have returned to their normally closed condition as mentioned. Consequently, the machine will automatically restart in the instance of a temporary tension irregularity for which machine shutdown is not required.

It will be noted that opening of switch S1 will allow the apparatus to operate in the conventional mode, i.e., wherein any operation of one of the stop-motion devices will shut down the machine.

In the above circuit, the main control relay C operates as a memory device and remains energized for a period of time after operation of a stop-motion device. The main control relay C remains thus energized until the period of timer T is complete, and then main control relay C will be deenergized if the tension irregularity remains. In that event, the machine will have to be inspected by an operator for correcting the yarn tension, and the machine will be manually restarted. However, the false stops usually associated with minor irregularities, will not require any attention of the operator and a manual restart.

The main control relay C indicates the motor has been started but has been shut down, thereby providing a circuit through contacts C1 for operating the timer. The tension is tested after a predetermined time and the machine restarted if the tension is correct, while the machine is shutdown and requires manual restart if the tension is incorrect at such time.

Although the present apparatus is described particularly in connection with a knitting machine, it will be realized the same is applicable to other apparatus including a start-stop system and a stop-motion device which indicates incorrect conditions for which shutdown is normally desired. The apparatus according to the present invention is particularly applicable to apparatus employing thread or yarn tension means.

While I have shown anddescribed a preferred embodiment of my invention, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from my invention in its broader aspects. 1 therefore intend the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What is claimed is:

1. in an apparatus for manufacturing a product from plural fibers including stop-motion devices for detecting predetermined tension in said fibers, an automatic restart circuit comprising:

means for arresting motion in said apparatus upon actuation of a said stop-motion device,

timing means also actuated in response to actuation of said stop-motion device for automatically reinitiating motion of said apparatus after a predetermined time,

and means coupled to said stop-motion device for preventing the automatic reinitiating of motion of said apparatus if a said stop-motion device remains actuated at the end of said predetermined time.

5 2. In an apparatus including motive means, a startstop system for said motive means, and a stop-motion device, an automatic restart circuit comprising:

a control means actuated when said start-stop system is actuated and by means of which said motive means is actuated, said control means retaining a particular condition after a starting operation of said start-stop system,

means coupling said stop-motion device for deactivating said motive means in response to change of state of said stop motion device,

and timing means actuated upon deactivation of said motive means and thereupon automatically changing said condition of said control means after a predetermined period of time if the changed state of said stop-motion device remains the same.

3. The apparatus according to claim 2 wherein said timing means further includes means for reactuating said motive means after said predetermined period of time if the last mentioned state of said stop-motion device has changed.

4. In an apparatus for manufacturing a product from plural fibers, said apparatus having a main control relay and a motor energizing relay for starting a motor,

means for starting the main control relay and the motor relay through contacts of the main control relay,

stop-motion means responsive to a condition of said fibers for breaking a first energizing circuit to the main control relay as well as a circuit to the motor relay for stopping the motor,

and timer means energized when the motor is deenergized, said timer means having contacts for breaking a second circuit to the main control relay after a predetermined period of time for thereby deenergizing the main control relay if the stop-motion means is still activated,

said timer means having further contacts for startin' the motor relay after a predetermined period of time if the stop-motion means is no longer activated. i I

5. The apparatus according to claim 4 wherein said further contacts of said timer means are connected for starting the motor relay through contacts of the main control relay if the stop-motion means is no longer activated.

6. The apparatus according to claim 4 wherein said timer means is energized through contacts of the main control relay.

7. The apparatus according to claim 4 wherein said starting means comprises a relay having contacts for initially energizing said main control relay and for initially energizing said motor relay, said last two mentioned relays also having holding contacts.

8. The apparatus according to claim 4 including a relay connected to energizing leads of said motor, said last mentioned relay having contacts for energizing said timer means when said motor is deenergized.

9. In apparatus including motive means and a stopmotion device responsive to a condition under which it is desired the apparatus be stopped, a control circuit comprising:

a starting relay responsive to manually initiated operation, said starrting relay having contacts,

a main control relay energizable through the contacts of said starting relay and having holding contacts for maintaining said main control relay in operation, said main control relay having further contacts,

a motor relay for energizing said motive means ener-' gizable through the contacts of said starting relay in combination with said further contacts of said control relay,

said stop-motion device operating contacts in circuit with said motor relay for deenergizing the same and in circuit with said main control relay,

and timer means operable when said motive means is deenergiz ed for deenergizing said main control relay after a predetermined time unless said stopmotion device has changed conditions, said timer means having contacts for energizing said motor relay in combination with said stop-motion device operating contacts in circuit with said motor relay.

10. The apparatus according to claim 9 wherein said timer means is energized via main control relay contacts.

11. A motor control system for a motor and including a stop-motion device responsive to a condition under which it is desired the motor be stopped, said system comprising:

a starting relay in series with a start button as well as normally closed contacts associated with said stopmotion device and normally closed contacts operable for opening upon energization of the controlled motor,

a main control relay in series with contacts on said starting relay, said control relay having holding contacts for maintaining energization thereof, said main control relay completing its circuit through further normally closed contacts controlled by said stop-motion device,

a motor relay adapted to be energized through contacts of said starting relay, contacts of said control relay, and normally closed contacts associated with said stop-motion device in series, said motor relay having holding contacts disposed in parallel with contacts of said starting relay,

and a timing relay adapted to be energized via the first mentioned contacts of said main control relay in series with contacts open when said motor is operating, said timing relay having first contacts in parallel with contacts of said starting relay, and having contacts in parallel with said normally closed contacts controlled by said stop-motion device.

12. The method of operating a knitting machine or the like, said machine including motive means and a stop-motion device, said method comprising:

actuating said stop motion device due to improper tension of yarn interrupting driving operation of said motive means upon actuation of said stop-motion device;

initiating a timing cycle when said driving operation is interrupted;

testing the condition of said stop-motion device at the end of said timing cycle;

automatically restarting said motive means if the tested condition of the stop-motion device indicates it is no longer activated;

and semi-permanently disabling said motive means if the tested condition of the stop-motion device indicates it is still activated, for requiring manual restart of said motive means.

13. The method of claim 12 including storing a previously on condition of said motive means only for the time period of said timing cycle, and automatically restarting said motive means at the end of the timing cycle only if said previously on condition is still stored. t 

1. In an apparatus for manufacturing a product from plural fibers including stop-motion devices for detecting predetermined tension in said fibers, an automatic restart circuit comprising: means for arresting motion in said apparatus upon actuation of a said stop-motion device, timing means also actuated in response to actuation of said stop-motion device for automatically reinitiating motion of said apparatus after a predetermined time, and means coupled to said stop-motion device for preventing the automatic reinitiating of motion of said apparatus if a said stop-motion device remains actuated at the end of said predetermined time.
 2. In an apparatus including motive means, a start-stop system for said motive means, and a stop-motion device, an automatic restart circuit comprising: a control means actuated when said start-stop system is actuated and by means of which said motive means is actuated, said control means retaining a particular condition after a starting operation of said start-stop system, means coupling said stop-motion device for deactivating said motive means in response to change of state of said stop motion device, and timing means actuated upon deactivation of said motive means and thereupon automatically changing said condition of said control means after a predetermined period of time if the changed state of said stop-motion device remains the same.
 3. The apparatus according to claim 2 wherein said timing means further includes means for reactuating said motive means after said predetermined period of time if the last mentioned state of said stop-motion device has changed.
 4. In an apparatus for manufacturing a product from plural fibers, said apparatus having a main control relay and a motor energizing relay for starting a motor, means for starting the main control relay and the motor relay through contacts of the main control relay, stop-motion means responsive to a condition of said fibers for breaking a first energizing circuit to the main control relay as well as a circuit to the motor relay for stopping the motor, and timer means energized when the motor is deenergized, said timer means having contacts for breaking a second circuit to the main control relay aftEr a predetermined period of time for thereby deenergizing the main control relay if the stop-motion means is still activated, said timer means having further contacts for starting the motor relay after a predetermined period of time if the stop-motion means is no longer activated.
 5. The apparatus according to claim 4 wherein said further contacts of said timer means are connected for starting the motor relay through contacts of the main control relay if the stop-motion means is no longer activated.
 6. The apparatus according to claim 4 wherein said timer means is energized through contacts of the main control relay.
 7. The apparatus according to claim 4 wherein said starting means comprises a relay having contacts for initially energizing said main control relay and for initially energizing said motor relay, said last two mentioned relays also having holding contacts.
 8. The apparatus according to claim 4 including a relay connected to energizing leads of said motor, said last mentioned relay having contacts for energizing said timer means when said motor is deenergized.
 9. In apparatus including motive means and a stop-motion device responsive to a condition under which it is desired the apparatus be stopped, a control circuit comprising: a starting relay responsive to manually initiated operation, said starrting relay having contacts, a main control relay energizable through the contacts of said starting relay and having holding contacts for maintaining said main control relay in operation, said main control relay having further contacts, a motor relay for energizing said motive means energizable through the contacts of said starting relay in combination with said further contacts of said control relay, said stop-motion device operating contacts in circuit with said motor relay for deenergizing the same and in circuit with said main control relay, and timer means operable when said motive means is deenergized for deenergizing said main control relay after a predetermined time unless said stop-motion device has changed conditions, said timer means having contacts for energizing said motor relay in combination with said stop-motion device operating contacts in circuit with said motor relay.
 10. The apparatus according to claim 9 wherein said timer means is energized via main control relay contacts.
 11. A motor control system for a motor and including a stop-motion device responsive to a condition under which it is desired the motor be stopped, said system comprising: a starting relay in series with a start button as well as normally closed contacts associated with said stop-motion device and normally closed contacts operable for opening upon energization of the controlled motor, a main control relay in series with contacts on said starting relay, said control relay having holding contacts for maintaining energization thereof, said main control relay completing its circuit through further normally closed contacts controlled by said stop-motion device, a motor relay adapted to be energized through contacts of said starting relay, contacts of said control relay, and normally closed contacts associated with said stop-motion device in series, said motor relay having holding contacts disposed in parallel with contacts of said starting relay, and a timing relay adapted to be energized via the first mentioned contacts of said main control relay in series with contacts open when said motor is operating, said timing relay having first contacts in parallel with contacts of said starting relay, and having contacts in parallel with said normally closed contacts controlled by said stop-motion device.
 12. The method of operating a knitting machine or the like, said machine including motive means and a stop-motion device, said method comprising: actuating said stop motion device due to improper tension of yarn interrupting driving operation of said motive means upon actuation of said stop-motion devIce; initiating a timing cycle when said driving operation is interrupted; testing the condition of said stop-motion device at the end of said timing cycle; automatically restarting said motive means if the tested condition of the stop-motion device indicates it is no longer activated; and semi-permanently disabling said motive means if the tested condition of the stop-motion device indicates it is still activated, for requiring manual restart of said motive means.
 13. The method of claim 12 including storing a previously on condition of said motive means only for the time period of said timing cycle, and automatically restarting said motive means at the end of the timing cycle only if said previously on condition is still stored. 